Marker delivery device with obturator

ABSTRACT

A marker delivery device includes an obturator having an elongated shaft, an internal lumen, a proximal end, and a substantially sealed distal end. The substantially sealed distal end is formed of a penetrable membrane. A marker delivery tube is configured to be slidably disposed within the internal lumen of the obturator. The marker delivery tube has a marker delivery lumen, a proximal end, and a distal tip. The marker delivery lumen is configured to contain one or more tissue markers. The distal tip is configured to puncture the penetrable membrane of the substantially sealed distal end of the obturator to form a passage through which the distal tip extends to facilitate delivery of the one or more tissue markers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is continuation of U.S. patent application Ser. No.11/499,466, filed Aug. 4, 2006, entitled, “MARKER DELIVERY SYSTEM WITHOBTURATOR”.

FIELD OF THE INVENTION

This invention relates generally to the field of medical devices andmethods. In particular, the invention relates to devices and methods formarking a biopsy site.

BACKGROUND OF THE INVENTION

In modern medical practice small tissue samples, known as biopsyspecimens, are often removed from tumors, lesions, organs, muscles andother tissues of the body. Such removal of tissue samples may beaccomplished by open surgical technique (i.e., removal of a small sampleof tissue through a small surgical incision using a local anesthetic),or through the use of a specialized biopsy instrument such as a biopsyneedle. After the tissue samples have been removed, they are typicallysubjected to diagnostic tests or examinations such as a) gross andmicroscopic examination to determine cytology and/or histology, b)biochemical analyses to determine the presence or absence of chemicalsubstances which indicate certain disease states, c) microbiologicalculturing to determine the presence of bacteria or other microbes,and/or d) other diagnostic procedures. The information obtained fromthese diagnostic tests and/or examinations can then be used to make orconfirm diagnoses and/or to formulate treatment plans for the patient.

When performing an image guided biopsy procedure an obturator is used asa place holder and is placed in tissue such that its tip will be locatedat the point in the patient's body where the biopsy is to be taken orwhere a biopsy site marker or tissue marker is to be placed after abiopsy procedure. Subsequent images are acquired that can confirm thecorrect placement of the obturator. When the obturator is placed at thedesired location within the body, blood can enter the lumen of theobturator prior to delivery of the tissue markers. This backflow ofblood into the obturator creates a risk of blood clotting.

Current obturators are constructed of homogeneous materials. Duringmagnetic resonance imaging (MRI) guided biopsies, the tip of theobturator is located by indexing through many cross sectional views(typically every 2 mm, but higher and lower discriminations arepossible). The material of the obturator will be distinguishable in thecross sectional images to a varying degree depending on the morphologyof the tissue and the obturator's own material makeup. Since theobturator is homogeneous, the signature of the obturator will not varyfrom one cross-sectional image to the next along its length. The tip ofthe obturator is located by selecting the first cross-sectional image inwhich the obturator is not seen. This result can be visually ambiguousdepending on the relative strength of the image signature of theobturator compared to the surrounding tissue.

After the biopsy sample is taken, it may take several days or weeksbefore the results of the examination of the sample are obtained, andstill longer before an appropriate treatment decision is reached. If thedecision involves surgery it is clearly important for the surgeon tofind the location in the breast from where the tumor tissue has beentaken in the biopsy procedure, so that the entire tumor and possiblysurrounding healthy tissue can be removed.

However, radiographically imageable tissue features, originally detectedin a mammogram, may be removed, altered or obscured by the biopsyprocedure. In order for the surgeon or radiation oncologist to directsurgical or radiation treatment to the precise location of the breastlesion several days or weeks after the biopsy procedure was performed,it is desirable that one or more biopsy site markers be placed in or onthe patient's body to serve as a landmark for subsequent location of thelesion. The purpose of such markers is to facilitate the surgicalprocedure that is performed while the marker is detectable.

The present invention provides a marker delivery device and method forplacing an obturator at the desired site in a patient's body as aplaceholder and for delivering such markers into the biopsy cavity.

SUMMARY OF THE INVENTION

This invention relates to devices and methods for placement of anintracorporeal object that functions as a marker, a therapeutic agent ora diagnostic agent and particularly for placing an obturator at adesired location within a patient's body and for delivering one or moreintracorporeal objects through the obturator to that location. Theobturator may operate as a place-holder during an image guided proceduresuch as a biopsy. The distal end of the obturator is placed where theprocedure is to be performed or one or more intracorporeal objects orbodies are to be delivered.

In one embodiment having features of the present invention the deviceincludes an obturator which has an elongated shaft with a internallumen, a proximal end, and a substantially sealed distal end whichprevents or minimizes the backflow of body fluids, such as blood, thoughthe lumen of the obturator. The substantially sealed distal end can be apenetrable membrane or may have petals or a duckbill-type valve whichare configured to allow passage of one or more intracorporeal objects ora delivery tube with one or more intracorporeal objects therethroughwhile preventing or minimizing entry of body fluids into the inner lumenof the obturator. Preferably the obturator is configured to fit within aprocedure cannula, e.g. a cannula of a biopsy device, for example, thecannula of SenoRx's EnCor™ Magnetic Resonance Imaging Breast BiopsySystem. The cannula provides access to the desired location within thepatient's body.

The delivery tube has a delivery lumen configured to contain one or moreintracorporeal objects. The distal tip is configured to penetrate thesubstantially sealed distal end of the obturator so that theintracorporeal bodies can be delivered while the obturator is in placewithin the body. The shape of the distal tip may be sharp or needle likewhen the sealed distal end of the obturator has a membrane or it may beblunt or rounded when the distal end of the obturator is petalled or hasa one-way valve.

The device preferably further includes a plunger having an elongatedshaft with a proximal portion and a distal portion. The plunger isconfigured to be slidably disposed within the lumen of the delivery tubeand is located proximal to the one or more intracorporeal objects withinthe lumen thereof. When the plunger is extended distally within thelumen, the distal end thereof moves one or more intracorporeal objectstoward and eventually through the distal end of the delivery tube. Theplunger preferably has an enlarged proximal end to prevent the distalportion of the plunger from advancing too far within the delivery lumen.Alternatively, a fluid may be used to advance the intracorporeal objectsthrough the opening.

A method for delivering one or more intracorporeal objects to a sitewithin a patient's body includes providing the above described device.The obturator is placed at a desired location within a patient's body.The delivery tube is advanced distally within the obturator until thedistal tip passes through the substantially sealed distal end of theobturator. Next the plunger is advanced distally within the deliverytube so that at least one intracorporeal object is pushed though theopening of the distal tip.

In one embodiment of the device the distal portion of the obturatorincludes a detectable element capable of producing a significant imagesignature at the location in the patient's body where the distal portionof the obturator is placed. Preferably this embodiment includes anobturator having an elongated shaft, a proximal end, a substantiallysealed distal end, and a detectable element, preferably in the form of aring at or near the distal end. A detectable element capable ofproducing a significant image signature is located adjacent to thesubstantially sealed distal end, preferably in the form of ring at thejunction between the distal tip and the elongated shaft.

The invention, in one form thereof, is directed to a marker deliverydevice. The marker delivery device includes an obturator having anelongated shaft, an internal lumen, a proximal end, and a substantiallysealed distal end. The substantially sealed distal end is formed of apenetrable membrane. A marker delivery tube is configured to be slidablydisposed within the internal lumen of the obturator. The marker deliverytube has a marker delivery lumen, a proximal end, and a distal tip. Themarker delivery lumen is configured to contain one or more tissuemarkers. The distal tip is configured to puncture the penetrablemembrane of the substantially sealed distal end of the obturator to forma passage through which the distal tip extends to facilitate delivery ofthe one or more tissue markers.

The invention, in another form thereof, is directed to a marker deliverydevice. The marker delivery device includes an obturator having anelongated shaft, an internal lumen, a proximal end, and a rounded distalend formed of a penetrable membrane. A marker delivery tube isconfigured to be slidably disposed within the internal lumen of theobturator. The marker delivery tube has a marker delivery lumen, aproximal end, and a distal tip. The marker delivery lumen is configuredto contain one or more tissue markers. The distal tip is configured topuncture the penetrable membrane of the rounded distal end of theobturator to form a passage through which the distal tip extends fordelivery of the one or more tissue markers.

The invention, in another form thereof, is directed to a method fordelivering a tissue marker to a site within a body of a patient. Themethod includes providing an obturator having an elongated shaft, aninternal lumen, a proximal end and a substantially sealed distal end,the substantially sealed distal end being formed of a penetrablemembrane; providing a marker delivery tube containing one or more tissuemarkers, the marker delivery tube having a distal tip; slidablydisposing the marker delivery tube within the internal lumen of theobturator; advancing the marker delivery tube within the internal lumenof the obturator toward the penetrable membrane of the substantiallysealed distal end of the obturator; and puncturing the penetrablemembrane of the substantially sealed distal end of the obturator withthe distal tip of the marker delivery tube to form a passage throughwhich the distal tip extends to facilitate delivery of the one or moretissue markers to the site.

The devices, systems, and methods of the present invention offerimproved delivery by minimizing the backflow of body fluids, such asblood, though the obturator lumen and thereby decreasing a risk of clotformation in the obturator. These and other advantages of the inventionwill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an elevational view of an assembly having features of theinvention including a marker delivery shaft and an obturator.

FIG. 1B is a transverse cross sectional view of the obturator of FIG. 1Ataken along line 1B-1B.

FIG. 1C is a transverse cross sectional view of the marker deliveryshaft of FIG. 1A taken along lines 1C-1C.

FIGS. 2A and 2B are elevational views of a delivery device embodyingfeatures of the invention wherein the distal tip of the marker deliveryshaft is proximal to the substantially sealed distal end. FIG. 2B isrotated 90° with respect to FIG. 2A.

FIG. 2C is a longitudinal cross sectional view taken along lines 2C-2Cin FIG. 2A.

FIG. 2D is a transverse cross sectional view taken along lines 2D-2D inFIG. 2A.

FIG. 3 is a perspective view of a substantially sealed distal end of anobturator having one or more petals.

FIG. 4 is a perspective view of a substantially sealed distal end of anobturator having a duck billed valve.

FIG. 5 is an elevational view of a distal tip of a marker deliverytubular shaft having a needle-like shape.

FIG. 6 is an elevational view of a distal tip of a marker deliverytubular shaft having a blunt end.

FIGS. 7A and 7B are elevational views of a distal portion of anobturator embodying features of the invention wherein the distal tip ofthe marker delivery shaft has partially punctured the substantiallysealed distal end of the obturator and the plunger is not yet deployed.FIG. 7B is rotated 90° with respect to FIG. 7A.

FIG. 7C is a longitudinal cross sectional view taken along line 7C-7C inFIG. 7A.

FIGS. 8A and 8B are elevational views of a distal portion of anobturator embodying features of the invention wherein the distal tip ofthe marker delivery shaft has completely punctured the substantiallysealed distal end of the obturator and the plunger is not yet deployed.FIG. 8B is rotated 90° with respect to FIG. 8A.

FIG. 8C is a longitudinal cross sectional view taken along lines 8C-8Cin FIG. 8A.

FIGS. 9A and 9B are elevational views of a distal portion of anobturator embodying features of the invention wherein the distal tip ofthe marker delivery shaft has completely punctured the substantiallysealed distal end of the obturator and the plunger is deployed. FIG. 9Bis rotated 90° with respect to FIG. 9A.

FIG. 9C is a longitudinal cross sectional view taken along line 9C-9C inFIG. 9A.

FIG. 10A is an elevational view of an obturator embodying features ofthe invention including a detectable element.

FIG. 10B is a cross-sectional view of the obturator shown in FIG. 10Ataken along line 10B-10B.

FIG. 10C is an enlarged view of Section 10C in FIG. 10A.

FIG. 10D is a longitudinal cross sectional view of the distal end of theobturator taken along line 10D-10D in FIG. 10C.

FIG. 10E is an enlarged view of section 10E shown in FIG. 10D.

FIG. 10F is a perspective view of the obturator wherein the distal endof the obturator, the detectable element, and the proximal portion ofthe obturator are shown separated.

FIG. 10G is an enlarged view of Section 10G shown in FIG. 10F.

FIG. 11A is an elevational view of an obturator embodying features ofthe invention including a plurality of detectable elements or bodieswithin the obturator.

FIG. 11B is a longitudinal cross-sectional view of the obturator shownin FIG. 11A taken along line 11B-11B.

FIG. 11C is a longitudinal cross-sectional view of the obturator as inFIG. 11B with the plunger distally advanced to discharge the detectableelements or bodies within the obturator.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A-2D shows an embodiment of a marker delivery device 10 havingfeatures of the invention including an obturator 12 and a markerdelivery tubular shaft 14. The obturator 12 has an elongated shaft 16,an internal lumen 18, a proximal end 20 and a substantially sealeddistal end 22. Preferably, as shown in FIGS. 2A-2D, the obturator 12 isconfigured to fit within a cannula 24 of a biopsy device, such asSenoRx's EnCor™ Magnetic Resonance Imaging (MRI) Breast Biopsy System.The cannula 24 provides access to the desired location within apatient's body. In some embodiments the cannula 24 includes depthmarkings 26 which indicate the distance which the obturator 12 hasadvanced within the patient's body.

The substantially sealed distal end 22 of the obturator 12 is configuredto prevent or minimize the backflow of fluids, such as body fluids,through the internal lumen 18 of the obturator 12. Preferably thesubstantially sealed distal end 22 is formed of a penetrable membrane28. As shown in FIGS. 1A, 2A, 2B and 2C, the substantially sealed distalend 22 of the obturator 12 has a rounded external surface and is formedof the penetrable membrane 28.

Alternatively the substantially sealed distal end 22 is formed of two ormore petals 30 (FIG. 3) or can be formed of a duck-billed valve 32 (FIG.4).

The marker delivery tubular shaft 14 is configured to be slidablydisposed within the internal lumen 18 of the obturator 12. The tubularshaft 16 has a marker delivery lumen 34 configured to contain one ormore tissue markers 36 for marking a biopsy site, a proximal end 38, anda distal tip 40 with an opening 42 for passage of one or more of themarkers 36. The tissue markers 36 may be those described in U.S. Pat.No. 6,996,433, U.S. Pat. No. 6,993,375, U.S. Pat. No. 6,862,470, U.S.Pat. No. 6,725,083, U.S. Pat. No. 6,662,041, U.S. Pat. No. 6,567,689,U.S. Pat. Nos. 6,427,081, 6,347,241, U.S. Pat. No. 6,161,034, U.S.patent application Ser. No. 10/444,770, U.S. patent application Ser. No.10/444,428, and U.S. patent application Ser. No. 10/001,043, which arehereby incorporated by reference. The marker delivery tubular shaft 14preferably also includes depth markings 44 which indicate the distancewhich the tubular shaft 14 has advanced within the obturator 12.

The distal tip 40 of the marker delivery shaft 14 is configured topenetrate the substantially sealed distal end 22 of the obturator 12 sothat tissue markers 36 can be delivered while the obturator 12 is inplace within the patient's body. Preferably the distal tip 40 is needleshaped 46 (FIG. 5), however, the distal tip can alternatively be a blunttip 48 (FIG. 6) which is capable of penetrating a substantially sealeddistal end 22 that is formed of a penetrable membrane 28 which isweakened or a distal end 22 with petals 30 or a valve 32.

Preferably the marker delivery device 10 also includes a plunger 50having an elongated shaft 52 with a distal end 54 and a proximal end 56.The plunger 50 is configured to be slidably disposed within the markerdelivery lumen 34 and is located proximal to the one or more tissuemarkers 36 within the marker delivery lumen 34. When the plunger 50 isextended distally within the marker delivery lumen 34 it moves one ormore tissue markers toward and eventually through the opening 42 in thedistal tip 40 of the marker delivery shaft 14. The plunger 50 preferablyhas an enlarged proximal end 58 to prevent its entry into the lumen 34.Alternatively, a fluid (not shown) may be used to advance the markers 36through the opening 42 in the distal tip 40 of the marker deliverytubular shaft 14.

FIGS. 7A-7C show the distal tip 40 of the marker delivery tube 14partially penetrating the substantially sealed distal end 22 of theobturator 12. In other words, as shown in FIGS. 7A-7C, the distal tip 40of the marker delivery tube 14 has partially punctured the penetrablemembrane 28 of the substantially sealed distal end 22 of the obturator12, and the plunger 50 is not yet deployed. The tissue markers 36 inFIG. 7A-7C are contained within the marker delivery lumen 34.

FIGS. 8A-8C show the distal tip 40 completely penetrating thesubstantially sealed distal end 22 of the obturator 12 and the tissuemarkers 36 within the marker delivery lumen 34. In other words, as shownin FIGS. 8A-8C, the distal tip 40 of the marker delivery tube 14 hascompletely punctured the penetrable membrane 28 of the substantiallysealed distal end 22 of the obturator 12, and the plunger 50 is not yetdeployed.

FIGS. 9A-9C show the distal tip 40 of the marker delivery tubular shaft14 completely penetrating the substantially sealed distal end 22. Inother words, as shown in FIGS. 9A-9C, the distal tip 40 of the markerdelivery tube 14 has completely punctured the penetrable membrane 28 ofthe substantially sealed distal end 22 of the obturator 12. In FIGS.9A-9C the plunger 50 is deployed distally within the marker deliverylumen 34.

Preferably the obturator 12 has a hub 60 at the proximal end 20 of theobturator shaft 16. The hub 60 may have gripping ridges 62 which allow aperson operating the device 10 to maintain a grip on the device 10. Themarker delivery tubular shaft 14 preferably also has a hub 64 at theproximal end of the marker delivery shaft 38 with gripping ridges 66. Atleast a portion of the hub 64 of the marker delivery tubular shaft 14 isconfigured to fit within the hub 64 of the obturator 12 when the markerdelivery shaft 14 is inserted into the obturator 12.

The marker delivery device 10 is preferably formed of a non-magneticmaterial. A plastic such as MAKROLON®, a polycarbonate from BayerMaterial Sciences a division of Bayer AG, is suitable and will notinterfere with a magnetic resonance imaging device (MRI). The device mayalso include a radiopaque material which allows for detection of thedevice. Alternatively the location of the obturator 12 may be determinedby detecting air within the elongated shaft 16 of the obturator 12 witha magnetic resonance imaging device (not shown).

A method for delivering a tissue marker to a site within a patient'sbody includes providing the above described device. The obturator 12 ofthe device 10 is inserted into a desired location within a patient'sbody. Preferably the obturator 12 is placed within the cannula 24 of abiopsy device that remains in the patient's body after the biopsy deviceis removed. The marker delivery tubular shaft 14 is then inserted intothe obturator 12 and the distal tip 40 of the tubular shaft 14 isadvanced through the substantially sealed distal end 22 of the obturator12. At least one tissue marker 36 within the marker delivery tubularshaft 14 is then advanced distally through the opening 42 in the distaltip 40 of the marker delivery tubular shaft 14. Preferably a plunger 50is advanced distally within the tubular shaft 14 so that at least onetissue marker 36 is moved through the opening 42 in the distal tip 40.Alternatively a fluid (not shown) can be used in place of the plunger tomove the tissue markers 36 through the distal tip 40.

An embodiment of the device having features of the invention, which isshown in FIGS. 10A-10G, includes an obturator 68 having an elongatedshaft 70 including a cylindrical wall with an internal lumen 72, aproximal end 74, a substantially sealed distal end 76, and a detectableelement 78 capable of producing a relatively significant imagesignature. Preferably the detectable element 78 is incorporated into theobturator 68 at a location determined to be optimum for complimentingthe subsequent procedure.

As shown in FIG. 10G, the detectable element 78 preferably is in theform of a ring 80 located near the substantially sealed distal end 76 ofthe obturator 68. Preferably the substantially sealed distal end 76 ofthe obturator 68 is located on an obturator tip 82. As shown in FIGS.10A, 10C, 10F and 10G, the detectable element 78/80 is in contact withthe mating surfaces of a terminal distal end of the cylindrical wall ofthe elongated shaft 70 and the obturator tip 82. The cylindrical wall ofthe elongated shaft 70 also includes at least one aperture 84 and theobturator tip 82 of the obturator 68 preferably includes a raised tab 86which extends into the aperture 84 to hold the obturator tip 82 inplace. The detectable element 78 in ring form 80 may be placed at thepoint where the obturator tip 82 and the elongated shaft 70 of theobturator 68 meet, i.e., at the junction between the obturator tip 82and the terminal distal end of the cylindrical wall of the elongatedshaft 70 of the obturator 68.

Preferably the detectable element 78 is in a form which allows theinternal lumen of the obturator 72 to remain unobstructed, such as aring 80. The detectable element 78 can also be a small sphere or rod,one or more wires, or a collar. Also any plan-form shape constructed ofsheet material, either planar or formed into a non-planar shape.Alternatively, the detectable element 78 may be the entire tip 82 of theobturator 68. Alternatively more than one detectable element 78 could beincorporated into the obturator 68 to be used as a marker capable ofdetermining the depth of the obturator 68 within a patient's body (notshown).

FIGS. 11A-C illustrate an alternative embodiment of an object deliverydevice 90 having features of the invention including an obturator 92which has an elongated shaft 94, an internal lumen 96, a proximal end 98and a substantially sealed distal end 100. Preferably, as previouslydiscussed with the other embodiments, the obturator 92 is configured tofit within a cannula of a biopsy device, such as SenoRx's EnCor™Magnetic Resonance Imaging (MRI) Breast Biopsy System. The substantiallysealed distal end 100 of the obturator 92 is configured to prevent orminimize the backflow of fluids, such as body fluids, through the innerlumen 96. A plurality of intracorporeal objects 102, e.g. biopsy sitemarkers, is disposed within the inner lumen 96. A plunger 104 with anenlarged head 106 is slidably disposed in part within the inner lumen 96proximal to the plurality of intracorporeal objects 102. Distal movementof the plunger 104 pushes the objects 102 through the distal end into abody site. In this embodiment, the intracorporeal objects may not beable to penetrate a membrane, so the substantially sealed distal end 100may be formed of two or more petals such as shown in FIG. 3 or can beformed of a duck-billed valve such as shown in FIG. 4.

Suitable materials for use as the detectable element 78 are metal,ceramic, metal filled plastic, mineral filled plastic, or a radiopaquematerial. Radiopaque materials such as stainless steel, platinum, gold,iridium, tantalum, tungsten, silver, rhodium, nickel, bismuth or otherradiopaque metals, mixtures of radiopaque metals, oxides of radiopaquemetals, barium salts, iodine salts, iodinated materials, andcombinations thereof are suitable as well. Additionally, MRI contrastagents such as Gadolinium and vitamin E may also be employed.

If desired, an imageable stylet may be used within the inner lumen ofthe sealed obturator to show the axis of the instrument and the depth ofthe insertion within the body. Preferably the stylet is formed ofmaterial which is compatible with MRI and which is seen in MRI generatedimages. Suitable materials include non-magnetic metals, non-magneticmetal filled plastics, hollow tubes filled at least in part with an MRIvisible substance such as Gadolinium or other fluids.

While particular forms of the invention have been illustrated anddescribed herein directed to detectable markers, it will be apparentthat various modifications and improvements can be made to theinvention. For example, the deployed bodies may be therapeutic ordiagnostic agents in addition to or in lieu of being markers. Moreover,individual features may be shown or otherwise described in oneembodiment and not in others, but those skilled in the art willrecognize that individual features of one embodiment of the inventioncan be combined with any or all the features of another embodiment.Accordingly, it is not intended that the invention be limited to thespecific embodiments illustrated.

Terms such as “element”, “member”, “component”, “device”, “means”,“portion”, “section”, “steps”, and words of similar import when usedherein shall not be construed as invoking the provisions of 35 U.S.C.§112(6) unless the following claims expressly use the term “means”followed by a particular function without reference to a specificstructure or the term “step” followed by a particular function withoutreference to a specific action. All patents and all patent applicationsreferred to above are hereby incorporated by reference in theirentirety.

1. A marker delivery device, comprising: an obturator having anelongated shaft, an internal lumen, a proximal end, and a substantiallysealed distal end, the substantially sealed distal end being formed of apenetrable membrane; and a marker delivery tube configured to beslidably disposed within the internal lumen of the obturator, the markerdelivery tube having a marker delivery lumen, a proximal end, and adistal tip, the marker delivery lumen being configured to contain one ormore tissue markers, and the distal tip being configured to puncture thepenetrable membrane of the substantially sealed distal end of theobturator to form a passage through which the distal tip extends tofacilitate delivery of the one or more tissue markers.
 2. The markerdelivery device of claim 1, wherein the substantially sealed distal endhas a rounded external surface.
 3. The marker delivery device of claim1, wherein the distal tip of the marker delivery tube is needle shaped.4. The marker delivery device of claim 1, wherein the proximal end ofthe obturator has a first hub and the proximal end of the markerdelivery tubular shaft has a second hub which is configured to fitwithin the first hub of the obturator when the marker delivery shaft isinserted into the elongated shaft of the obturator.
 5. The markerdelivery device of claim 1, which is made of non-metallic material. 6.The marker delivery device of claim 1, which is made of non-magneticmaterial.
 7. The marker delivery device of claim 1, wherein thesubstantially sealed distal end is a sealed distal end.
 8. A markerdelivery device, comprising: an obturator having an elongated shaft, aninternal lumen, a proximal end, and a rounded distal end formed of apenetrable membrane; and a marker delivery tube configured to beslidably disposed within the internal lumen of the obturator, the markerdelivery tube having a marker delivery lumen, a proximal end, and adistal tip, the marker delivery lumen being configured to contain one ormore tissue markers, and the distal tip being configured to puncture thepenetrable membrane of the rounded distal end of the obturator to form apassage through which the distal tip extends for delivery of the one ormore tissue markers.
 9. The marker delivery device of claim 8, whereinthe distal tip of the marker delivery tube is needle shaped.
 10. Themarker delivery device of claim 8, wherein the proximal end of theobturator has a first hub and the proximal end of the marker deliverytubular shaft has a second hub which is configured to fit within thefirst hub of the obturator when the marker delivery shaft is insertedinto the elongated shaft of the obturator.
 11. The marker deliverydevice of claim 8, which is made of non-metallic material.
 12. Themarker delivery device of claim 8, which is made of non-magneticmaterial.
 13. The marker delivery device of claim 8, wherein thesubstantially sealed distal end is a sealed distal end.
 14. A method fordelivering a tissue marker to a site within a body of a patient,comprising: providing an obturator having an elongated shaft, aninternal lumen, a proximal end and a substantially sealed distal end,the substantially sealed distal end being formed of a penetrablemembrane; providing a marker delivery tube containing one or more tissuemarkers, the marker delivery tube having a distal tip; slidablydisposing the marker delivery tube within the internal lumen of theobturator; advancing the marker delivery tube within the internal lumenof the obturator toward the penetrable membrane of the substantiallysealed distal end of the obturator; and puncturing the penetrablemembrane of the substantially sealed distal end of the obturator withthe distal tip of the marker delivery tube to form a passage throughwhich the distal tip extends to facilitate delivery of the one or moretissue markers to the site.
 15. The method of claim 14, comprisingadvancing a plunger through a marker delivery lumen of the markerdelivery tube to advance at least one tissue marker through the distaltip of the marker delivery tube to the site.